The core facility will consolidate all the morphological services for the use of the various projects. These services include histological preparations such as tissue processing, embedding sectioning and staining. Following histological processing the core will provide evaluation and interpretation of histopathological changes in tissue sections. These include evaluation and quantification of demyelination during coronavirus infection in mice, evaluation of virus-induced cerebrovascular disease in murine leukemia virus infection in mice, and analysis of HSV receptor expression in human brain. Computerized morphometric analysis will be offered as necessary. Additional morphological services or assistance will be provided for studies which require immunohistochemistry, immunofluorescence, in situ hybridization, in situ-PCR, and electron microscopy. Thus the core facility services are essential to the success of the fundamental goal of the project.